Fuels for internal combustion engines



United States Patent Office 3,080,221 Patented Man- 5, 1 963 3,080,221 FUELS FOR INTERNAL COMBUSTION ENGINES "Karl Niitz'el, Koln-S tammheim, and Rudolf Stroh, Eugen Hiinri'l'en, arid Walter Lohrn'ar, Leverkusen, Germany, -assignors to Farbenfabriken Bayer Aktieng'esellsc'haft,

Leverkusen, Germany, a corporation of Germany No Drawing. Filed Jan. 24, 1961, Ser. No. 84,525

The present invention relates to'fuels for internal comb'ustion engines of the spark ignition type, especially to motor fuels for cars and airplanes; more particularly it concerns motor fuels consisting of gasoline or mixtures 'ofgasoline' and benzene. According to the invention these fuels contain "boroncompounds of the general formula B'AHI3 wherein the three Ar represent the same or different aromatic radicals which are substituted by at least three aliphatic hydrocarbon radicals having 1-10 carbon atoms, two of the hydrocarbon radicals being in o,o-position to the boron atom.

Owing to the presence of boron compounds of the above general formula the tendency of the motor fuels to form deposits in the combustion engines is minimized. This applies particularly to motor fuels which contain anti-knock agents, for instance lead compounds such as lead tetraethyl, or aromatic amines such as monomethyl aniline, N-methyl-p-toluidine and xylidine or mixtures thereof. Furthermore the boron compounds improve the octane number of the fuels and prevent the progressive increase in the minimum requirements for the fuels on prolonged operation of the engines.

Suitable boron compounds of the formula indicated are for instance boron trimesityl of the formula CHa and boron triduryl of the formula CHa H; C- CH;

These compounds can be obtained by reacting boron ,trifluoride with the Grign ard compounds of trimesityl- :chl oride, triisopropylph'enylchloride or durylchloride in known manner. H

The conte'ntfof the boron compounds in the fuels ma vary'within'wide limits. It may for instance amount to .001%-5% by volume. The ratios depend in the first place upon the content of the anti-knock agents in the motor fuels; suitable ratios can easily be determined by preliminarytes'ts. I, g V

I The following examples serve to illustrate theinventi'on without, however,lim'iting'the scope thereof.

Example 1 A gasoline whose physico-chemical data are indicated below was mixed with.03% by volume of lead tetraethyl and 05% by volume of boron trimesityl, boron tris triisopropylphenyl or boron triduryl. With this fuel afour cylinder'motor was'operated under ch'angingload for 25 hours without interruption. After this time only about 5% of the surface of the pistons were covered with a light, very thin weakly brownish coating. The pistons did not show further alterations. On the bottom of the pistons and on the walls of the combustion cham bers a slight coating of a white greyish powder was observed, but no hard carbonaceous deposits of combustion residues were present. In the suction system no alterations could be observed.

The physico-chemical data of the gasoline used were as follows.

When the test was carried out under equal conditions with the same gasoline and with the addition of .03% by volume of lead tetraethyl but Without the addition of boron trimesityl, boron tristriisopropylphenyl or boron triduryl 22% of the surface of the pistons were covered with a lacquer-like coating and the bottom of the pistons as Well as the walls of the combustion chambers were covered with hard carbonaceous combustion residues.

If .05% by volume of boron triphenyl which is known as additive to motor fuels, was aplied instead of the boron compounds of the invention, 17% of the surface of the pistons were covered with a lacquer-like coating; besides, disturbances occurred in the carburetor on account of cloudy precipitates.

Example 2 A gasoline having the same physico-chamical data as the gasoline of Example 1 but which did not contain lead tetraethyl was mixed with .5'% by volume of boron trimesityl. The octane number determined by the F method (ASTM D90851) in the IG-motor test amounted to 71.1; with the addition of 1% by volume of boron trimesityl it amounted to 71.6 whereas without the addition of boron trimesityl the octane number was 70.7.

When instead of .5% by volume of boron trimesityl the same amount of boron tristriisopropylphenyl or boron triduryl was applied the octane number was 72.7 or 72.1 respectively. 1 r

Very remarkable is the stability the boron compounds of the invention exhibit in the motor fuels. If for instance a solution of 5 g. of boron trimesityl, 5g. of boron tristriisopropylphenyl or 5 g. of boron triduryl in 60 ml. of a benzene-ligroin mixture is shaken with 40 ml. of water and kept standing at room temperature for 70 hours, no hydrolysis of the boron compounds can be observed. If however a solution of 5 g. of boron triphenyl in 60 m1. of a benzene-ligroin mixture is shaken with 40 ml. of Water and kept standing at room temperature for 70 hours, 29% by weight of the boron tri phenyl are hydrolysed and have become inefficient.

What We claim:

'1. A motor fuel for an internal combustion engine of the spark ignition type, comprising a component selected from the group consisting of gasoline, benzene, and an admixture of gasoline and benzene, together with about .001% to 5% by volume of a boron compound having the general formula B-AR wherein Ar represents an aromatic radical having at least three aliphatic hydrocarbon substituents having from A} a about 1 to 10 carbon atoms, twobf said aliphatic hy drocarbon substituents being in o,o-position with respect to the boron atom.

2. A motor fuel according to claim 1 wherein the boron compound is selected from the group consisting of boron trimesityl, boron tristriisopropylphenyl and boron triduryl.

3. A motor fuel according to claim 1 containing at least one antiknock additive selected from the group consisting of lead tetraethyl, monoethyl aniline, N-methylp-toluidine, and xylidine.

References Cited in the file of this patent UNITED STATES PATENTS 2,410,846 Walters Nov. 12, 1946 FOREIGN PATENTS 549,075 Great Britain Nov. 5, 1942 OTHER REFERENCES Boron New Improvement Agent, an article by Hughes et al. in Refining Engineering, vol. 28, No. 7, July 1956, pages C10Cl3. 

1. A MOTOR FUEL FOR AN INTERNAL COMBUSTION ENGINE OF THE SPARK IGINTION TYPE, COMPRISING A COMPONENT SELECTED FROM THE GROUP CONSISTING OF GASOLINE, BENZENE, AND AN ADMIXTURE OF GASOLINE AND BENZENE, TOGETHER WITH ABOUT .001% TO 5% BY VOLUME OF A BORON COMPOUND HAVING THE GENERAL FORMULA 